Magnetic multi-pole electric switch



May 3, 1966 B. J. WARMAN MAGNETIC MULTI-POLE ELECTRIC SWITCH Filed Aug. 11, 1964 2 2 255 8. QwSmzzoo United States Patent F land, a British company Filed Aug. 11, 1964, Ser. No. 388,851 Claims priority, application Great Britain, Aug. 12, 1963,

1 Claim. (Cl. 200-87) This invention relates to electric switches, and more specifically to. electric switches of the magnetic type.

In light-current electrical systems, such as for example telecommunication systems, it has hitherto been usual to employ a multi-point connecting device of the plug (or pin) and socket (or jack) type to perform the function of connecting, in a manner permitting ready disconnection for testing and fault finding purposes, a circuit or item of equipment to an associated circuit or item of equipment.

In general, unless it is of relatively expensive construction, a multi-point connecting device of the type referred to suifers from the disadvantage that it in itself introduces a fairly high fault hazard into the system concerned.

The present invention has in view the provision of an improved form of multi-pole electric switch which is suited for use, in place of a multi-point connecting device of the type referred to, for performing the function of connecting, in a manner permittingready disconnection for testing and fault finding purposes, a circuit or item of equipment to an associated circuit .or item of equipment, and which has a very high degree of reliability, and which can be produced relatively cheaply.

A multi-pole electric switch in accordance with the invention comprises a plurality of reed-contact units-of the kind comprising two reeds of electrically-conductive magnetic material that extend towards and partly overlap each other within asealed enclosure and that when subjected to an operating magnetic field are attracted towards each other to establish 'electrical contact between them but separate-owing to their inherent tension on the removal of such field. 7

Each one of the reed-contact units has attached thereto three terminals; a first terminal, a second terminal, and a third terminal. The first and third terminals of each reed-contact unit come together and are in permanent electrical connection with the outer end of the same one of the two reeds of the reed contact unit. The second terminal is in electrical connection with the outer end of the other reed-contact of the reed contact unit. To facilitate the explanation of the invention the first terminal of all of the reed-contact units will be referred to hereinafter collectively as the first group of terminals." Similarly, all of the second terminals and third terminals will be referred to hereinafter collectively as the second group of terminals and third group of terminals respectively. The switch has a connect condition in which the two reeds of all the units are brought together thereby connecting the terminals of the first group to their corresponding terminal of the second group; and a disconnectedv condition in which the reeds are separated so that the first group of terminals and the corresponding terminals of the second group of contacts are not connected. Thus it can be seen that the purpose of the device is to control the connection between the first group and second group of terminals.

The third terminal of each reed-contact unit, or the third group of terminals, is of an auxiliary nature. These third terminals, which are for purposes of testing and fault finding, are employed when the first and second groups of terminals are in the disconnect condition. These terminals are of such a form, and are so located in the switch, as to be adapted to be engaged by respective correspond- 3,249,715 Patented May 3, 1966 ing members of a multi-point plug or socket, used to obtain access (e.g. for testing purposes), when the switch is in the disconnect condition With the removable magnetic part (explained in more detail below) removed therefrom, to a circuit or item of equipment connected to the terminals of the first group.

A removable permanently-magnetized magnetic part serves, as long as it is in position in the switch, to maintain the switch in the connect condition by providing an operating magnetic field for each of the reed-contact units. The removal of this magnetic part from the switch serves to bring the switch to the disconnect condition. The removable magnetic part is in the form of a plate having an edge portion bent to form a mask serving, when the magnetic part is in position in the switch, to prevent a multipoint connector as referred to from being brought into engagement with the terminalsof the third group and to shield these terminals from accidental contact.

Reed-contact units of the kind referred to are of course used in so-called reed relays, and, as at the present time the use of such relays is growing rapidly, it is contemplated that manufacture in increasing quantities is likely to cause reed-contact units of the kind concerned to become progressively cheaper, causing an electric switch according to the invention to become progressively cheaper. It will be appreciated by those skilled in the art that such a switch has a very high degree of reliability.

An electric switch in accordance with the invention may be employed, for example,'for connecting a circuit or item of equipment to a group of signal and information highways in a manner permitting ready isolation of the circuit or item of equipment from the highways.

A plurality of electric multi-pole switches in accordance with the invention each including a plurality of reedcontact units may be provided with a common removable magnetic part capable of serving them one at a time, it being thereby ensured that only one switch of the plurality can be in the connect condition at a time. In an arrangement of this nature which is especially envisaged, a pair of similar electric switches in accordance with the invention (which switches may conveniently be arranged Side by side) are provided with a common removable permanently-magnetised magnetic part capable of serving them one at a time, and one switch, when in the connect condition connects a first circuit or item of equipment to a group of signal and information highways, and the other switch, when in the connect condition connects a standby circuit or item of equipment, corresponding to the first circuit or item of equipment, to this group of highways. The nature of the invention will be clearer fromthe description of a specific embodiment of it which will now be given with reference to the accompanying drawing. This embodiment takes the form of an electric switch having a connect condition in which it connects each of nine terminal members constituting a first group of terminals of the switch individually to the corresponding one of nine terminal members constituting a second group of terminals of the switch. The single figure of the drawing is a perspective view showing the switch with certain portions cut away and removed, and with the removable permanently-magnetised magnetic part of the switch withdrawn from the switch to cause the switch to be in the disconnect condition.

The switch comprises a moulded main mounting member 1 formed of insulating material. In the drawing, this member is shown with a right-hand (as seen in the drawing) portion cut away and removed, but itscomplete shape will be obvious if it is borne in mind that the member is symmetrical with respectto a vertical plane containing the axis of the central reed contact unit, designated X in the drawing. The nine terminals 5 constitute the third group of terminals of the switch. The first group of terminals consisting of the nine terminals 3, and the second group of terminals consist of the nine terminals 4. The drawing shows the switch with the right-hand reed-contact unit and its three terminals removed. The switch comprises nine reed-contact units 6, of which only eight appear in the drawing. As is represented in the drawing, each of these reed-contact units comprises two reeds (which are of course of electrically-conductive magnetic material) that ext-end towards and partly overlap each other within a sealed enclosure but are separated by a gap in the absence of an operating magnetic field. Two slots 9 (of which only the left-hand one appears in the drawing) in the main mounting member I serve to accommodate edge portions of, and locate, the removable permanentlymagnetised magnetic part 2 of the switch when this part is inserted in position in the switch. The magnetic part 2 is provided with a handle 8 to facilitate its insertion into, and removal from, the switch, and is magnetised in the manner indicated by the N and S polarity markings in the drawing.

As regards each pair of terminals of a given reed-contact unit, terminal 3 of the first group and the corresponding terminal 4 of the second group, the terminal 3 of the pair has, for connecting purposes within the unit, a relatively long extension 10 which is connected (e.g.'by soldering) to the outer end of one of the reeds (together with the terminal 5 of the third group of terminals of the switch). The terminal 4 of the pair is connected to the outer end of the other reed of the reed-contact unit. Upon the insertion of the removable permanently-magnetised magnetic part 2 in position in the switch so that it has been pushed as far as possible along the slots 9, this plate provides an operating magnetic field for connecting each pair of reeds of the nine reed-contact units, with the consequence that the switch'is brought to the connect condition in which it connects each of the nine terminal members 3 of the first group individually to the corresponding one of the nine terminal members 4 of the second group. The switch remains in the connect condition, of course, as long as the magnetic part 2 is in position in it.

The terminals 5 of the third group are terminals adapted to be engaged by respective corresponding members of a multi-point connector, in the form of a multi-point socket or jack, used to obtain access, when the switch is in the disconnect condition with the removable magnetic part removed therefrom, to a circuit or item of equipment connected to the terminals 3 of the first group.

The removable part 2 is in the form of a plate havin an edge portion 7 to which the handle 8 is secured, and which is bent to form a mask serving, when the magnetic part is in position in the switch, to prevent a multi-point connector as just referred to from being brought into engagement with the terminals 5 of the third group and to shield these terminals from accidental contact. tent to which the magnetic part 2 can be pushed along the slots 9 is limited by the abutment of the edge 11 of this part with the face 12 of the main mounting member 1, and is such that-the edge or mask portion 7 stands clear of contact with the terminals 5 when the magnetic part has been pushed as far as possible along the slots 9.

. What .I claim is:

A magnetic multi-pole electric switch comprising a plurality of magnetically operable reed-contact units, each said unit having a first terminal, a second terminal and a third terminal, the first terminals'of all the units comprising the first group of terminals, the second terminals of all the units comprising the second group of terminals, and the third terminals of all the units comprising the third group of terminals, the first and third terminals of each unit being in permanent electrical connection with each other and with one reed of the reed contact unit, and the second terminal of each unit being in permanent electrical connection with the other reed of the unit, and a removq able permanently-magnetised magnetic part adapted to be mounted in position on the switch to provide an operating magnetic field for each of the reed-contact units, said magnetic part being in the form of a plate having an edge portion bent to form a mask serving to mask the terminals of the third group when the magnetic part is mounted in position in the switch.

References Cited by the Examiner UNITED STATES PATENTS 2,124,156

BERNARD A. GILHEANY, Primary Examiner.

B. DOBECK, Assistant Examiner.

The ex- 

